The present invention relates to a method of generating a group key between a plurality of nodes which are group members, and more particularly, to an effective and practical method of generating a group key using a Diffie-Hellman algorithm.
An online conference is a method of sharing opinions while looking at each other and hearing each other's voices without having to come face to face with each other, and reduces physical and temporal expenses. Accordingly, meetings online are increasing as compared to meetings offline, and applications such as a remote video conferencing programs are being developed. The online conference, handling various subjects in various environments, may involve confidential information that must not be leaked, and that must be exposed to no one except to members of the online conference. Accordingly, a plurality of nodes form one group in a certain environment, such as an online conference, and perform encryption in order to avoid data from being exposed outside the group while sharing the data. In various encryption algorithms for protecting the data, a key for data encryption is pre-distributed between the nodes. However, distributing an encryption key in an unsecured channel is an important issue.
A group key is agreed so as to provide a session key to members of the group that wish to securely communicate through an open communication network. Specifically in a mobile computing environment, the resources of devices are limited, and thus it is essential to use energy efficiently during a group key agreement process.
Key exchanging techniques include a Diffie-Hellman technique in which nodes share a key when there are not any secured channels. However, the Diffie-Hellman technique is not suitable for a plurality of nodes to exchange a key. Various group key setting mechanisms using the Diffie-Hellman technique exist, but conventional technologies are unpractical since many operations need to be performed as the conventional technologies require an order of exchanging messages or have a large number of messages to be transmitted. Accordingly, a method of simply generating a group key by exchanging messages only once without an order or a chain by using a master node is suggested herein.